package com.example.demo.util.common;/**
 * Created by penglee on 2019/7/2.
 */

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.Validate;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

import java.lang.reflect.*;

/**
 * ReflectionUtils
 * <p>
 * Description: 反射工具类.
 * 提供调用getter/setter方法,
 * 访问私有变量,
 * 调用私有方法,
 * 获取泛型类型Class,
 * 被AOP过的真实类等工具函数.
 * Created in 2019/7/2 09:15 <br>
 *
 * @author 李鹏
 */
@Slf4j
public class ReflectionUtils {
    private static final String SETTER_PREFIX = "set";
    private static final String GETTER_PREFIX = "get";
    private static final String CGLIB_CLASS_SEPARATOR = "$$";

    /**
     * Description: invokeGetter
     * 调用Getter方法.支持多级，
     * 如：对象名.对象名.方法
     * Params: [obj, propertyName]
     * Return: java.lang.Object
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static Object invokeGetter(Object obj, String propertyName) {
        Object object = obj;
        for (String name : StringUtils.split(propertyName, "." )) {
            String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(name);
            object = invokeMethod(object, getterMethodName, new Class[]{}, new Object[]{});
        }
        return object;
    }

    /**
     * Description: invokeSetter
     * 调用Setter方法, 仅匹配方法名。
     * 支持多级，如：对象名.对象名.方法
     * Params: [obj, propertyName, value]
     * Return: void
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static void invokeSetter(Object obj, String propertyName, Object value) {
        Object object = obj;
        String[] names = StringUtils.split(propertyName, "." );
        for (int i = 0; i < names.length; i++) {
            if (i < names.length - 1) {
                String getterMethodName = GETTER_PREFIX + StringUtils.capitalize(names[i]);
                object = invokeMethod(object, getterMethodName, new Class[]{}, new Object[]{});
            } else {
                String setterMethodName = SETTER_PREFIX + StringUtils.capitalize(names[i]);
                invokeMethodByName(object, setterMethodName, new Object[]{value});
            }
        }
    }

    /**
     * Description: getFieldValue
     * 直接读取对象属性值,
     * 无视private/protected修饰符, 不经过getter函数.
     * Params: [obj, fieldName]
     * Return: java.lang.Object
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static Object getFieldValue(final Object obj, final String fieldName) {
        Field field = getAccessibleField(obj, fieldName);
        if (field == null) {
            throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]" );
        }
        Object result = null;
        try {
            result = field.get(obj);
        } catch (IllegalAccessException e) {
            log.error("不可能抛出的异常{}", e.getMessage());
        }
        return result;
    }

    /**
     * Description: setFieldValue
     * 直接设置对象属性值,
     * 无视private/protected修饰符, 不经过setter函数.
     * Params: [obj, fieldName, value]
     * Return: void
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static void setFieldValue(final Object obj, final String fieldName, final Object value) {
        Field field = getAccessibleField(obj, fieldName);
        if (field == null) {
            log.error("Could not find field [" + fieldName + "] on target [" + obj + "]" );
            return;
            //throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
        }
        try {
            field.set(obj, convert(value, field.getType()));
        } catch (IllegalAccessException e) {
            log.error("不可能抛出的异常:{}", e.getMessage());
        }
    }

    public static Object convert(Object object, Class<?> type) {
        if (object instanceof Number) {
            Number number = (Number) object;
            if (type.equals(byte.class) || type.equals(Byte.class)) {
                return number.byteValue();
            }
            if (type.equals(short.class) || type.equals(Short.class)) {
                return number.shortValue();
            }
            if (type.equals(int.class) || type.equals(Integer.class)) {
                return number.intValue();
            }
            if (type.equals(long.class) || type.equals(Long.class)) {
                return number.longValue();
            }
            if (type.equals(float.class) || type.equals(Float.class)) {
                return number.floatValue();
            }
            if (type.equals(double.class) || type.equals(Double.class)) {
                return number.doubleValue();
            }
        }
        if (type.equals(String.class)) {
            return object == null ? "" : object.toString();
        }
        return object;
    }

    /**
     * Description: invokeMethod
     * 直接调用对象方法, 无视private/protected修饰符.
     * 用于一次性调用的情况，否则应使用getAccessibleMethod()函数获得Method后反复调用.
     * 同时匹配方法名+参数类型，
     * Params: [obj, methodName, parameterTypes, args]
     * Return: java.lang.Object
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static Object invokeMethod(final Object obj, final String methodName, final Class<?>[] parameterTypes,
                                      final Object[] args) {
        Method method = getAccessibleMethod(obj, methodName, parameterTypes);
        if (method == null) {
            throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]" );
        }
        try {
            return method.invoke(obj, args);
        } catch (Exception e) {
            throw convertReflectionExceptionToUnchecked(e);
        }
    }

    /**
     * Description: invokeMethodByName
     * 直接调用对象方法, 无视private/protected修饰符，
     * 用于一次性调用的情况，否则应使用getAccessibleMethodByName()函数获得Method后反复调用.
     * 只匹配函数名，如果有多个同名函数调用第一个。
     * Params: [obj, methodName, args]
     * Return: java.lang.Object
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static Object invokeMethodByName(final Object obj, final String methodName, final Object[] args) {
        Method method = getAccessibleMethodByName(obj, methodName);
        if (method == null) {
            throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]" );
        }
        try {
            return method.invoke(obj, args);
        } catch (Exception e) {
            throw convertReflectionExceptionToUnchecked(e);
        }
    }

    /**
     * Description: getAccessibleField
     * 循环向上转型, 获取对象的DeclaredField, 并强制设置为可访问.
     * 如向上转型到Object仍无法找到, 返回null.
     * Params: [obj, fieldName]
     * Return: java.lang.reflect.Field
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static Field getAccessibleField(final Object obj, final String fieldName) {
        Validate.notNull(obj, "object can't be null" );
        Validate.notBlank(fieldName, "fieldName can't be blank" );
        for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {
            try {
                Field field = superClass.getDeclaredField(fieldName);
                makeAccessible(field);
                return field;
            } catch (NoSuchFieldException e) {
                // Field不在当前类定义,继续向上转型
                continue;
            }
        }
        return null;
    }

    /**
     * Description: getAccessibleMethod
     * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
     * 如向上转型到Object仍无法找到, 返回null.
     * 匹配函数名+参数类型。
     * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
     * Params: [obj, methodName, parameterTypes]
     * Return: java.lang.reflect.Method
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static Method getAccessibleMethod(final Object obj, final String methodName,
                                             final Class<?>... parameterTypes) {
        Validate.notNull(obj, "object can't be null" );
        Validate.notBlank(methodName, "methodName can't be blank" );
        for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
            try {
                Method method = searchType.getDeclaredMethod(methodName, parameterTypes);
                makeAccessible(method);
                return method;
            } catch (NoSuchMethodException e) {
                // Method不在当前类定义,继续向上转型
                continue;
            }
        }
        return null;
    }

    /**
     * Description: getAccessibleMethodByName
     * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
     * 如向上转型到Object仍无法找到, 返回null.
     * 只匹配函数名。
     * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
     * Params: [obj, methodName]
     * Return: java.lang.reflect.Method
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static Method getAccessibleMethodByName(final Object obj, final String methodName) {
        Validate.notNull(obj, "object can't be null" );
        Validate.notBlank(methodName, "methodName can't be blank" );
        for (Class<?> searchType = obj.getClass(); searchType != Object.class; searchType = searchType.getSuperclass()) {
            Method[] methods = searchType.getDeclaredMethods();
            for (Method method : methods) {
                if (method.getName().equals(methodName)) {
                    makeAccessible(method);
                    return method;
                }
            }
        }
        return null;
    }

    /**
     * Description: makeAccessible
     * 改变private/protected的方法为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
     * Params: [method]
     * Return: void
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static void makeAccessible(Method method) {
        if ((!Modifier.isPublic(method.getModifiers()) || !Modifier.isPublic(method.getDeclaringClass().getModifiers()))
                && !method.isAccessible()) {
            method.setAccessible(true);
        }
    }

    /**
     * Description: makeAccessible
     * 改变private/protected的成员变量为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
     * Params: [field]
     * Return: void
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static void makeAccessible(Field field) {
        if ((!Modifier.isPublic(field.getModifiers()) || !Modifier.isPublic(field.getDeclaringClass().getModifiers()) || Modifier
                .isFinal(field.getModifiers())) && !field.isAccessible()) {
            field.setAccessible(true);
        }
    }

    /**
     * Description: getClassGenricType
     * 通过反射, 获得Class定义中声明的泛型参数的类型, 注意泛型必须定义在父类处
     * 如无法找到, 返回Object.class.
     * 如public UserDao extends HibernateDao<User>
     * Params: [clazz]
     * Return: java.lang.Class<T>
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    @SuppressWarnings("unchecked" )
    public static <T> Class<T> getClassGenricType(final Class clazz) {
        return getClassGenricType(clazz, 0);
    }

    /**
     * Description: getClassGenricType
     * 通过反射, 获得Class定义中声明的父类的泛型参数的类型.
     * 如无法找到, 返回Object.class.
     * 如public UserDao extends HibernateDao<User,Long>
     * Params: [clazz, index]
     * Return: java.lang.Class
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static Class getClassGenricType(final Class clazz, final int index) {
        Type genType = clazz.getGenericSuperclass();
        if (!(genType instanceof ParameterizedType)) {
            log.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType" );
            return Object.class;
        }
        Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
        if (index >= params.length || index < 0) {
            log.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "
                    + params.length);
            return Object.class;
        }
        if (!(params[index] instanceof Class)) {
            log.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter" );
            return Object.class;
        }
        return (Class) params[index];
    }

    public static Class<?> getUserClass(Object instance) {
        Assert.notNull(instance, "Instance must not be null" );
        Class clazz = instance.getClass();
        if (clazz != null && clazz.getName().contains(CGLIB_CLASS_SEPARATOR)) {
            Class<?> superClass = clazz.getSuperclass();
            if (superClass != null && !Object.class.equals(superClass)) {
                return superClass;
            }
        }
        return clazz;
    }

    /**
     * Description: convertReflectionExceptionToUnchecked
     * 将反射时的checked exception转换为unchecked exception.
     * Params: [e]
     * Return: java.lang.RuntimeException
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {
        if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException
                || e instanceof NoSuchMethodException) {
            return new IllegalArgumentException(e);
        } else if (e instanceof InvocationTargetException) {
            return new RuntimeException(((InvocationTargetException) e).getTargetException());
        } else if (e instanceof RuntimeException) {
            return (RuntimeException) e;
        }
        return new RuntimeException("Unexpected Checked Exception.", e);
    }

    /**
     * Description: hasField
     * 判断某个对象是否拥有某个属性
     * Params: [obj, fieldName]
     * Return: boolean
     * CreateDate: Created in
     * Modify:
     * Author: 李鹏
     */
    public static boolean hasField(final Object obj, final String fieldName) {
        Field field = getAccessibleField(obj, fieldName);
        return field != null;
    }
}
